1. Field of the Invention
The present invention relates to a power adapter, and, more particularly, to a power adapter with a combinational plug.
2. Description of the Related Art
Power adapters serve to be connected between electric appliances and the mains power and are provided to convert AC (Alternating Current) power supplied by the mains power into DC (Direct Current) power required by electric appliances. The worldwide voltage values of the mains power fall in a range of 100 V to 240 V, and can be classified into a high-voltage standard and a low-voltage standard. The voltage values of the high-voltage standard fall between 220 V and 240 V, and the voltage values of the low-voltage standard fall between 100 V and 120 V.
A conventional power socket has two sets of plug terminals, and each set of plug terminals is selectively plugged into a power socket of a receptacle with a corresponding specification. The specifications of the two sets of plug terminals differ from each other for the power adapter to be plugged into two types of power sockets with different specifications. The two sets of plug terminals are pivotally and oppositely mounted on the power socket so that they can be pivoted along two opposite directions and require less space for storage. When in use, one set of plug terminals is ready to be plugged into a matching power socket by pivoting the set of plug terminals to be erected. When stored, the set of plug terminals is received in containing slots of the power socket. To convert AC power supplied by the mains power into DC power required by electric appliances, the power socket is usually mated with a matching power adapter supporting an operating voltage range between 100 V and 240 V. Due to the wide voltage range to be supported, multiple conversion circuits are required and the circuit design of the power socket becomes more complicated.
Although the mating conventional power socket and a matching power adapter can support a wide range of mains power, both are complicated in terms of structure and circuit design thereof. Such complexity leads to higher production cost. As far as user's perspective is concerned, the use of the mating conventional socket and the matching power adapter is meaningless and wasteful unless the user has a frequent need for international travel and charging to portable electronic products.